From ae75bf96c41bf8ec7563149889ff5358925e9a8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20=C3=96hrstr=C3=B6m?= <oehrstroem@gmail.com>
Date: Sat, 7 May 2022 19:40:46 +0200
Subject: [PATCH] Auto-detect ascii in model-version vif.

---
 src/dvparser.cc       | 18 +++++++++++++-----
 src/testinternals.cc  | 26 ++++++++++++++++++++++++++
 src/util.cc           | 32 ++++++++++++++++++++++++++++++++
 src/util.h            |  2 ++
 tests/test_analyze.sh |  2 +-
 5 files changed, 74 insertions(+), 6 deletions(-)

diff --git a/src/dvparser.cc b/src/dvparser.cc
index c681efc..414b573 100644
--- a/src/dvparser.cc
+++ b/src/dvparser.cc
@@ -417,10 +417,11 @@ bool parseDV(Telegram *t,
 
         DVEntry *dve = &(*dv_entries)[key].second;
 
+        /*
         if (isDebugEnabled())
         {
             debug("(dvparser) entry %s\n", dve->str().c_str());
-        }
+        }*/
 
         assert(key == dve->dif_vif_key.str());
 
@@ -949,10 +950,17 @@ bool DVEntry::extractReadableString(string *out)
         t == 0x7 || // 64 Bit Integer/Binary
         t == 0xD)   // Variable length
     {
-        // For example an enhanced id 32 bits binary looks like:
-        // 44434241 and will be reversed to: 41424344 and translated using ascii
-        // to ABCD
-        v = reverseBinaryAsciiSafeToString(v);
+        if (isLikelyAscii(v))
+        {
+            // For example an enhanced id 32 bits binary looks like:
+            // 44434241 and will be reversed to: 41424344 and translated using ascii
+            // to ABCD
+            v = reverseBinaryAsciiSafeToString(v);
+        }
+        else
+        {
+            v = reverseBCD(v);
+        }
     }
     if (t == 0x9 || // 2 digit BCD
         t == 0xA || // 4 digit BCD
diff --git a/src/testinternals.cc b/src/testinternals.cc
index eda7dca..29b2929 100644
--- a/src/testinternals.cc
+++ b/src/testinternals.cc
@@ -48,6 +48,7 @@ void test_hex();
 void test_translate();
 void test_slip();
 void test_dvs();
+void test_ascii_detection();
 
 int main(int argc, char **argv)
 {
@@ -82,6 +83,7 @@ int main(int argc, char **argv)
     test_translate();
     test_slip();
     test_dvs();
+    test_ascii_detection();
 
     return 0;
 }
@@ -1254,3 +1256,27 @@ void test_dvs()
         printf("ERROR test_dvs 1\n");
     }
 }
+
+void test_ascii_detection()
+{
+    string s = "000008";
+    if (isLikelyAscii(s))
+    {
+        printf("ERROR >%s< should not be likely ascii\n", s.c_str());
+    }
+    s = "41424344";
+    if (!isLikelyAscii(s))
+    {
+        printf("ERROR >%s< should be likely ascii\n", s.c_str());
+    }
+    s = "000041424344";
+    if (!isLikelyAscii(s))
+    {
+        printf("ERROR >%s< should be likely ascii\n", s.c_str());
+    }
+    s = "000041194300";
+    if (isLikelyAscii(s))
+    {
+        printf("ERROR >%s< should not be likely ascii\n", s.c_str());
+    }
+}
diff --git a/src/util.cc b/src/util.cc
index 505265a..c0f8e62 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -2192,3 +2192,35 @@ void removeSlipFraming(vector<uchar>& from, size_t *frame_length, vector<uchar>
     }
 
 }
+
+// Check if hex string is likely to be ascii
+bool isLikelyAscii(std::string v)
+{
+    vector<uchar> val;
+    bool ok = hex2bin(v, &val);
+
+    // For example 64 bits:
+    // 0000 0000 4142 4344
+    // is probably the string DCBA
+
+    if (!ok) return false;
+
+    size_t i = 0;
+    for (; i < val.size(); ++i)
+    {
+        if (val[i] != 0) break;
+    }
+
+    if (i == val.size())
+    {
+        // Value is all zeroes, this is probably a number.
+        return false;
+    }
+
+    for (; i < val.size(); ++i)
+    {
+        if (val[i] < 20 || val[i] > 126) return false;
+    }
+
+    return true;
+}
diff --git a/src/util.h b/src/util.h
index 4267b52..2984dfd 100644
--- a/src/util.h
+++ b/src/util.h
@@ -43,6 +43,8 @@ uchar reverse(uchar c);
 std::string reverseBCD(std::string v);
 // A hex string encoding ascii chars is reversed and safely translated into a readble string.
 std::string reverseBinaryAsciiSafeToString(std::string v);
+// Check if hex string is likely to be ascii
+bool isLikelyAscii(std::string v);
 
 bool isHexChar(uchar c);
 
diff --git a/tests/test_analyze.sh b/tests/test_analyze.sh
index b1d797f..1ee64e1 100755
--- a/tests/test_analyze.sh
+++ b/tests/test_analyze.sh
@@ -142,7 +142,7 @@ Using driver : multical21(driver should be upgraded) 00/00
 019   : 78 tpl-ci-field (EN 13757-3 Application Layer (no tplh))
 020   : 02 dif (16 Bit Integer/Binary Instantaneous value)
 021   : FF vif (Vendor extension)
-022   : 20 vife (per second)
+022   : 20 combinable vif (PerSecond)
 023 C!: 7100 info codes (DRY(dry 22-31 days))
 025   : 04 dif (32 Bit Integer/Binary Instantaneous value)
 026   : 13 vif (Volume l)